Which is worse: a direct-to-video sequel to a hit film, or a direct-to-video sequel that’s so much a sequel-in-name-only that it turns out the thing was made under a different title, then rechristened by a greedy studio when executives realized how much more rental business they could snare if they loaned it the name of a previous hit?

Such is the story of “Open Water 2: Adrift,” a European production which lands on the DTV market in the States after getting a full release elsewhere around the globe last year under the simpler title “Adrift.” Lionsgate purchased the thing for American distribution, but only after noticing such comments like the one made by The Guardian’s Peter Bradshaw, who called it “almost a conceptual sequel” (indeed, almost every European review mentions comparisons to “Open Water;” in addition to the stranded-in-the-ocean theme, both declare they are “inspired by true events”). DTV sequels being the big business they are these days, Lionsgate quickly grabbed the copycat and changed it into a follow-up.

“Adrift” is pretty much “Open Water” with three times the people and zero times the sharks. Our story begins as a bunch of old pals reunite for a relaxing yacht weekend off the coast of Mexico. The characters are cheap, broad types: the douchebag, the slutty idiot, the party gal, the party guy, the nice gal, and her dopey nice guy of a husband. (Also along for the trip: Nice Gal and Dopey Nice Guy’s baby daughter, who’s not old enough to be given a type, unless “Sleepy Baby” counts.)

For dramatic purposes, Nice Gal is terrified of water, having witnessed her father’s drowning years back. This vacation is a huge step forward in conquering her fears, and yes, it’s ultimately impossible to look past the cheapness of this plot device (flashbacks throughout pump in shoddy attempts at dramatic tension, especially in the finale) and the inconsistencies of the whole mess (she won’t step on board the boat without a life jacket, yet never bothers to put any sort of floatie on her kid).

One afternoon, they all decide to go for a dip, except for Nice Gal, of course - until Douchebag thinks it’d be hilarious to grab her and dive overboard. But the real joke’s on Douchebag: before jumping off, he forgot to lower the ladder, thus leaving all six idiots floating along with no way of getting back on board.

With no sharks (or any other form of fishy threat) coming their way, the only possible tension must come instead from amping up each character’s idiocies and turning the entire cast into a heap of unlikable twits. Slutty Idiot goes crazy quickly, screaming and crying and trying to steal Nice Gal’s life jacket. Everybody yells at Douchebag for being a douchebag. And every effort to escape back onto the yacht is foiled by a parade of ineptitude. (Watching the film becomes a game of “Why Don’t They…?” Make up your own questions about the various unused possible rescue methods. It’s fun!)

Of course, this being a thriller, the cast must die off one by one. But with nothing else around, it’s up to the characters to die from their own stupidities. One guy bumps his head. Another guy swallows too much sea water. Others fall to similar efforts by the filmmakers to keep things interesting by any measure. In a better film, such deaths would be interesting and/or heartbreaking, as the characters would have by now gained our sympathies, or at least our attention. Here, with only a bunch of obnoxious, underdeveloped jerks to watch, it is impossible to care about who’s gone, and why, and how. As such, we multiply the “just hurry up and die” impatience of “Open Water” to a furious “please, I’m begging you, just drown already” vibe this time around. (Even the addition of a baby on board, waiting for her mother’s return, fails to infuse the audience with the slightest bit of concern.)

And while director Hans Horn manages to overcome the redundancies of the screenplay with tight pacing and a few sharp visuals (for all its faults, the film is effectively staged), and while the young cast does a decent job breathing life into their undercooked characters, the film can’t keep from evolving from dull to detestable thanks to a finale that irritates in its attempts to be shockingly clever. (The film delivers several fake-out endings before stumbling upon the actual one, an open-ended number that would’ve worked fine if not for the trickery that comes before it.)

So even without intending to be, “Adrift” becomes exactly the sort of DTV sequel we so very often ignore. It’s “Open Water” reworked as a fumbling suspense-free time killer. Adrift, indeed.